This is a supplemental request to ongoing support for a scanning electron microscope to pursue the cytological part of my morphological and biochemical studies on the nervous control of regeneration of body parts in the vertebrate and on the ependymal role in spinal cord regeneration. The research concerns 1) a search for a morphological assay of our neurotrophic agent using the taste buds of the fish barbel. Our present method is a biochemical one showing that a nervous extract can recover the protein synthesis in the regenerate lost after denervation, 2) a study of the regenerate cells from various stages in salamander limb regrowth and the relation of nerve fibers to them, 3) the role of the ependyma and its processes in channeling the early axonal patterns during spinal cord regeneration in the salamander and lizard. Justification for the instrument is based on my specific research needs and the unavailability of a scanning EM in the medical complex. However, I assure NIH that once installed the microscope will not sit idle since there are other researchers supported by various grants who need and will use the scope when it is available. Their researches and personal histories are appended to demonstrate the nature of their use of such an instrument.